Exact expressions for minor hysteresis loops in the random field Ising model on a Bethe lattice at zero temperature

Shukla, Prabodh

doi:10.1103/physreve.63.027102

Cited by 28 publications

(5 citation statements)

References 8 publications

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“…Remarkably, the loop shift field, jH shift j, as obtained from m FC versus H curves (figure 2) and plotted versus T in figure 4, does not show any anomaly at T c , but continues to increase monotonically as T is lowered ( figure 4, open squares). This is compatible with the report [18] that minor loop shifts are related to the skewness of the corresponding major loop rather than to its width 2H c . Three of our criteria for a low-T collective SFM state in the FeCo particle system were also recently observed for a-Co-Ni-B nanoparticles with diameter d % 3 nm [12].…”

Section: Dense Frozen Ferrofluidsupporting

confidence: 91%

“…Very probably, this effect has nothing to do with the unidirectional anisotropy (exchange bias) induced at AF/FM interfaces after proper FC procedures [17]. It is rather due to the properties of so-called minor loops in disordered systems, which memorize the sign of the initial field when performing incomplete hysteresis cycles [18].…”

Section: Dense Frozen Ferrofluidmentioning

confidence: 99%

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Intra- and interparticle interaction in a dense frozen ferrofluid

et al. 2005

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The zero field cooled (ZFC) and field cooled (FC) low-field magnetic moment m of a dense frozen ferrofluid containing Fe 55 Co 45 particles of size 4.6 nm in hexane exhibits irreversibility at temperatures T < T b % 30 K. FC in m 0 H 1 T gives rise to shifted minor hysteresis loops below T b . At T c % 10 K, sharp peaks of m ZFC and of the ac susceptibility 0 , a kink of the thermoremanent magnetic moment m TRM , a sizeable reduction of the coercive field H c , and the appearance of a spontaneous moment m SFM indicate a phase transition with near mean-field critical behaviour of both m SFM and 0 . These features are explained within a core-shell model of nanoparticles, whose strongly disordered shells gradually become blocked below T b , while their soft ferromagnetic cores couple dipolarly and become superferromagnetic (SFM) below T c .

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Section: Dense Frozen Ferrofluidsupporting

confidence: 91%

Section: Dense Frozen Ferrofluidmentioning

confidence: 99%

Intra- and interparticle interaction in a dense frozen ferrofluid

et al. 2005

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“…Mainly the interest was focused on the non-equilibrium physics of the RFIM, as it emerged as a very effective model for Barkhausen noise and hysteresis in magnets (see [16] and references therein). Much efforts over the years have been made to characterize analytically the outof-equilibrium magnetization [16], correlation functions [17], hysteresis loops [18], and expansions toward fully connected models [19], just to mention few. The out-of-equilibrium Glauber dynamics too was solved in [20].…”

Section: The Modelmentioning

confidence: 99%

Improved belief propagation algorithm finds many Bethe states in the random-field Ising model on random graphs

Perugini

Ricci-Tersenghi

2018

Phys. Rev. E

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We first present an empirical study of the Belief Propagation (BP) algorithm, when run on the random field Ising model defined on random regular graphs in the zero temperature limit. We introduce the notion of extremal solutions for the BP equations, and we use them to fix a fraction of spins in their ground state configuration. At the phase transition point the fraction of unconstrained spins percolates and their number diverges with the system size. This in turn makes the associated optimization problem highly non trivial in the critical region. Using the bounds on the BP messages provided by the extremal solutions we design a new and very easy to implement BP scheme which is able to output a large number of stable fixed points. On one hand this new algorithm is able to provide the minimum energy configuration with high probability in a competitive time. On the other hand we found that the number of fixed points of the BP algorithm grows with the system size in the critical region. This unexpected feature poses new relevant questions about the physics of this class of models.

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“…However, often it is experimentally impractical to take magnets to their saturation point due to the large magnetic fields required, so the behavior of subloops ( figure 22, (74)) is of great interest to experiments and applications. The RFIM can be used to model subloops, and in one dimension (75) and on a Bethe lattice (76; 77) they have been computed exactly (78). The magnetization curves of subloops have been collapsed near the demagnetized state using Rayleigh's law (12; 79).…”

Section: A Return-point Memorymentioning

confidence: 99%

Random-Field Ising Models of Hysteresis

Sethna

Dahmen

Perkovic³

2006

The Science of Hysteresis

110

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This is a review article of our work on hysteresis, avalanches, and criticality. We provide an extensive introduction to scaling and renormalization-group ideas, and discuss analytical and numerical results for size distributions, correlation functions, magnetization, avalanche durations and average avalanche shapes, and power spectra. We focus here on applications to magnetic Barkhausen noise, and briefly discuss non-magnetic systems with hysteresis and avalanches.

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Exact expressions for minor hysteresis loops in the random field Ising model on a Bethe lattice at zero temperature

Abstract: We obtain exact expressions for the minor hysteresis loops in the ferromagnetic random field Ising model on a Bethe lattice at zero temperature in the case when the driving field is cycled infinitely slowly.

Cited by 28 publications

References 8 publications

Intra- and interparticle interaction in a dense frozen ferrofluid

Intra- and interparticle interaction in a dense frozen ferrofluid

Improved belief propagation algorithm finds many Bethe states in the random-field Ising model on random graphs

Random-Field Ising Models of Hysteresis

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